Effect of PEG pretreatment on germination,growth and its drought-resistance of hulless barley | PEG预处理对青稞种子萌发、幼苗生长和抗旱性的影响

Chinese. 以抗旱性弱的青稞品种‘大麻青稞’为材料，研究不同质量分数（5％～30％）聚乙二醇（PEG）预处理对其种子萌发、幼苗生长和抗旱性的影响。结果表明，1）随着PEG预处理质量分数的增加，‘大麻青稞’种子的发芽率和生根率，幼苗的根长、苗高和鲜重均呈先增加后降低的趋势；种子的发芽率、生根率、幼苗的根长和苗高均在10％的PEG处理下值最高，分别为对照的L14、1．05、1．24和1．33倍，且除生根率外，其他指标均与对照差异极显著（P〈0．01）；叶片可溶性蛋白和叶绿素先增加后降低，而丙二醛含量和相对电导率则先降低后增加，并在15％PEG处理下最佳，分别为对照的1．38、1．84、0．65和0．71倍，且与对照差异极显著（P〈0．01）；2）当幼苗经30％PEG重度胁迫时，其叶片蛋白质和叶绿素含量分别比胁迫前下降42．11％和38．98％，而经15％PEG预处理的两者含量比胁迫对照组提高了42．80％和1．01倍；经30％PEG重度胁迫后相对电导率和丙二醛含量分别比胁迫前上升了28．24％和6．04%，而经15％PEG预处理的两者含量比胁迫对照组降低了28．64％和33．41％。表明低质量分数的PEG对青稞种子的萌发和幼苗的生长生理特性具有促进作用，高质量分数的PEG处理对植物的生长产生了抑制作用。

English. To explore the regulation of the polyethylene glycol（PEG） on drought-resistance of hulless barley,effects of 5%-30% of PEG pretreatment on its seed germination, seedling growth and drought-resistant were examined. The results were as the following： 1 ） Germination and rooting rate in hulless barley seed, root length, shoot height and fresh weight in Dama hulless barley seedlings showed ＇ rising first and failing later＇ with the increase of PEG concentration. The best treatment concentration on germination and rooting rate, root length and shoot height was 10% and the difference was significant with the control（ P〈0. 01） except for rooting rate,which was 1. 14, 1.05, 1.24 and 1.33 times respectively as control. Soluble protein and chlorophyll content in leaves showed ＇ rising first and falling later＇, however malondialdehyde（MDA） content and relative conductivity showed ＇falling first and rising later＇. The best treatment concentration was 15 % and the difference was significant with the control（ P〈0.01 ）, which was 1.38,1.84, 0.65 and 0.71 times respectively as control. 2） Compared with non-30% of PEG,soluble protein and chlorophyll content in leaves showed a remarkable decline and the malondialdehyde（MDA） content and relative conductivity showed a significant increase when the seedling suffering from 30% of PEG,but the above indexes of seedling pretreated by 15% of PEG were restricted obviously. Such as soluble protein and chlorophyll content decreased by 42.11% and 38.98% as control after suffering from 30% of PEG, but both were increased 42. 80% and 1. 01 times by 15% of PEG pretreatment; malondialdehyde（MDA） content and relative conductivity increased by 28.24% and 6.04% as control after suffering from 30% of PEG,but both were decreased 28.64% and 33.41% by 15% of PEG pretreatment. To sum up,PEG has a dual effect on the regulation of plant drought-resistance. At lower concentration, it can promote seed germination, seedling growth and its physiological function, but at higher concentration, it can inhibit plant growth through disrupting the cell membrane,degrading protein and chlorophyll. The results of this study suggested that PEG can make dormant seed rapidly active using a proper concentration of PEG solution to soak, and improve the efficiency of seed breeding,which lays a foundation for the PEG widely application in agriculture.